FR2694334A1 - Manually guided drilling tool. - Google Patents

Abstract

Known manual guided drilling tools, provided with a guide handle, a control motor, a gearbox and a clutch arranged between the engine the gearbox can give rise, when the drill abuts against resistances in the borehole, at unexpected increases in torque which cause a sudden decrease in the speed of rotation and / or a jamming of the drill, in which case the braking torque thus produced also endangers the user. To remedy this, there is provided on the drilling tool a trigger lever (2) put into working relationship with the braking mechanism (3) so that, for a predefined limit value of an untimely rotational movement of the 'drilling tool, due to the fact that the drill (18) collides against a resistance to drilling, the trigger lever triggers the braking mechanism.

Description

The present invention relates to a tool

  drill to be guided manually, provided with a guide handle, a

  control motor, gearbox and clutch

  centrifugal age placed between the engine and the gearbox. Manually guided drilling tools of this kind have the disadvantage that in the case where the drill collides with resistances in the borehole, for example stones, roots or the like, there are unexpectedly increases in torque which lead to a

  sudden decrease in the speed of rotation of the drill or even

  me to a catch or jamming The braking torque thus

  if the product must be absorbed by the user via the

  guide handles, which poses a risk

  considerable accident since the user can, by acting

  thus losing control of the tool and thus injuring yourself

  ser. The object of the present invention is to produce the drilling tool defined above in such a way that the

  cited disadvantages are avoided and the risk of accident

  existing tooth is reliably removed by means

  simple in construction.

  This goal is achieved, for a drilling tool with a guide

  manually and fitted with a guide handle, a

  control unit, a gearbox and an em-

  centrifugal clutch placed between the engine and the gearbox

  braids, according to the invention by the fact that on the forming tool

  rage are provided a trigger lever and a mechanism

  braking in working relationship with this

  deny that in addition the trigger lever is connected, in terms of operation, to the braking mechanism so that, for a predefined limit value of an untimely rotational movement of the drilling tool due to the fact that the

  drill bit comes up against resistance to drilling, the lever

  trigger activates the braking mechanism In addition, the trigger lever is advantageously mounted mobile, on a

  carrier body, against the retaining force of a spring

positioning spell.

  In an exemplary embodiment, the lever triggers

  cheur is provided with an inert mass which is dimensioned in such a way that in case of exceeding a limit value of the involuntary and sudden angular acceleration of

  the drilling tool the retaining force that holds the

  in the rest position, i.e. in the released position of the braking mechanism,

  found defeated and braking is triggered The limit value

  te is then a predefined quantity of the angular acceleration

  area which occurs during the rotation of the drilling tool

  The fact that the drill comes up against resistance to drilling.

ge.

  In another embodiment the lever

  trigger having an inert mass is connected to another trigger lever which is preferably produced under the

  shaped like a lever bar that can extend laterally

  ralement beyond the drilling tool, in the extension of the trigger lever provided with an inert mass In this case

  the additional bar-shaped release lever is also

  Lement mounted movable, on the carrier body, against the retaining force of a positioning spring In such an embodiment the braking mechanism can also be triggered in case of exceeding the value of an angular acceleration or of a predefined angular size, namely when the trigger lever shaped

bar abuts the user.

  In a third embodiment the mechanism

  braking is only activated when the lever disengages

  bar-shaped latch that projects laterally

  apart from the drilling tool, travels during the rotation

  tion of the drilling tool due to the fact that the drill stops against resistance to drilling, an angular interval which is determined by the fact for the trigger lever to abut against the user In this embodiment the trigger lever can be constituted exclusively of a lever bar of comparatively small mass, preferably even without mass, so that the braking mechanism is triggered when this bar

  forming a lever abuts the body of the user.

  The trigger lever formed by a bar can advance

  taggingly present a joint, for example under the

  shaped like a coil spring, so that its part

  external tie, by hitting a stop, can deflect under-

  bends with respect to the interior.

  The safety braking mechanism according to the

  vention therefore makes it possible to obtain that in the event of a collision of the drill with resistances in the borehole the increase in

  torque thus acting on the drilling tool, provided with

  guide pins, or instantly prevented by braking the centrifugal clutch drum Under these conditions the

  drive torque is absorbed via the ru-

  brake ban, and a rotation of the drilling tool and, consequently, also the risk for the user of being injured

are avoided.

  In a simple embodiment of the drilling tool according to the invention, the carrier body of the braking mechanism comprises at least one of the following constituent elements: a brake band, a positioning spring, a tension spring, a joint toggle switch as well as the trigger lever hingedly connected to the latter and provided with an inert mass, advantageously mounted on the trigger lever so as to be movable in

  the longitudinal direction of the latter, and / or a lever

  bar-shaped clapper These elements together form the braking mechanism This can, in a form of

  advantageous realization, to be made as a separate piece

  independent intermediate configured in such a way that it can be incorporated in a simple way between the control motor and the gearbox of the drilling tool On

  this intermediate piece can advantageously be pre-

  seen from the fixing elements making it possible to connect it by clamping to the engine and to the gearbox, these fixing elements preferably being holes in the carrier body intended to receive fixing screws. Such an embodiment of the braking mechanism has with the advantage that the construction cost can remain low and that there is no need to make changes to the construction method

  other components of such a drilling tool.

  In addition, in the case where the braking mechanism is produced in the form of an intermediate piece, any drilling tool

  existing can easily and quickly be retrofitted

riori of the safety mechanism.

  Another characteristic of the invention consists

  in that the carrier body comprises the drum of the clutch-

  centrifugal age and in that the clutch drum has a motor pinion to connect it in form connection to the

  gearbox, the clutch drum being furthermore

  wrapped in brake tape and fixed at one end to the carrier body, the other free end of the brake tape

  being, by means of the articulation with ge-

  noodle, in working relationship with the trigger lever

and the tension spring.

  Advantageously, the positioning spring is produced as a leaf spring which is applied with a

  end on the release lever, while it is supported

  tee at its other end by the carrier body, and the tensioning spring is produced as a drawing spring

  tion between the load-bearing body and the toggle joint.

  According to another characteristic of the invention, the

  tension spring, toggle joint, spring

  positioning spell and a terminal part, preferably

  this cubit, of the trigger lever with its articulation axis are arranged, eccentric with respect to an at least approximately circular recess formed in the body

  carrier, in at least one neighboring recess.

  When the intermediate piece and the housing of the

  gearbox are brought together to form a single

  appears the brake band is advantageously placed around the clutch drum arranged in the gearbox housing and the other components of the safety braking mechanism, namely the positioning spring, the tension spring, the articulation to knee pad and mass

  inert are housed in the recess making at least partly

  tie protruding laterally beyond the gearbox housing. The invention is described in more detail below with the aid of exemplary embodiments illustrated in the appended drawings in which:

  Figure 1 is an exploded view of a tool for

  complete rage with a first example of realization of a

  safety braking mechanism; FIG. 2 shows, also in exploded view, the safety braking mechanism of FIG. 1 integrated into the casing of the gearbox of the drilling tool;

  FIG. 3 represents a second example of a

  setting of the safety braking mechanism with a bar forming an additional lever for the trigger lever;

  Figure 4 shows a third example of a

  in which the triggering of the brake mechanism

  swimming is carried out, without any particular inert mass, only by means of a bar forming a trigger lever; FIG. 5 represents, in radial section through the carrier body, the construction of a braking mechanism

  safety suitable for all examples of implementation.

  The exemplary embodiments shown show a drilling tool to be guided manually and comprising guide handles 17, 17 ′, a control motor 4 with a gearbox 14 as well as a centrifugal clutch 1 which, placed between the motor 4 and the gearbox 14,

  comprises a clutch drum 10 and a motor pinion 11.

  The user guides this drilling tool from a position

  tion, located behind the drawing plane of Figure 1, holding with the right hand the handle 17 located on the left on

  the figure and on which the ne-

  switches 17 a and the throttle 17 b.

  According to the invention there is provided on the forming tool

  rage a trigger lever 2 (see Figures 1 to 3) as well

  that a safety braking mechanism 3 located in re-

  Working relationship with the latter The trigger lever 2 and the braking mechanism 3 are, in terms of their operation, interconnected so that for

  a predefined limit value of a rotational movement

  of the drilling tool due to the fact that the drill collides with resistances in the borehole, for example stones, roots or the like, the braking mechanism 3 is

found triggered.

  To this end the trigger lever 2 is mounted displaceable against the retaining force of a positioning spring 7 so that it has a path

limited maneuvering.

  In the embodiment of FIG. 1, the trigger lever 2 has a predefined inert mass, the magnitude of which is such that, if a limit value of the angular acceleration of the drilling tool is exceeded, it l 'prevails on the retaining force of the trigger lever 2, provided with an inert mass, in the released position of the braking mechanism 3, and initiates braking. In this embodiment, it is mounted on

  the trigger lever a movable inert mass 16 of such

  the way that the magnitude of the angular acceleration for

  which the trigger lever 2 should trigger the mechanism

braking me 3, is adjustable.

  The trigger lever 2 has, relative to the braking mechanism 3, in particular relative to the body

  carrier 5 of the braking mechanism 3, a short path of ma-

  works in such a way that when the limit value of

  the angular acceleration is reached, it passes into the po-

  braking position and can be brought back by the user

  only in the starting position where the

braking is released.

  Consequently, the mechanism according to the invention makes it possible to obtain that, in the presence of a resistance to drilling at the level of the drill 18, the latter is braked, for a predefined acceleration limit value of the increase in torque, up to 'idling so that any subsequent rotation of the drilling tool and therefore any risk to the user of being injured are avoided. In the embodiment of Figure 3 the

  trigger lever 2 has no additive inert mass

  onnelle 16 and is provided, through its place

  of articulation 20 on the carrying body 5, of a lever

  additional actuator 2 presented in the form of a bar projecting laterally beyond the drilling tool and which is also subjected to the retaining force of the spring

  positioning 7 and has an appropriate maneuvering path

  required for brake activation The brake is triggered when in the event of resistance to drilling the drilling tool is made to rotate so that the free end of trigger lever 2 has struck the user and therefore triggers a short subsequent rotation of the drilling tool,

  braking The limit value in this case is the inter-

  angular valleys that the trigger lever 2 travels, during the rotation of the drilling tool, until it abuts against the user If the drill bit 18 turns in a clockwise direction (see the arrow N) then, at the moment when the drill stops against a resistance, the drilling tool is caused to perform, as a result of the reaction force,

  in the opposite direction, that is to say the opposite of the ai-

  watch faces, a determined angular path, rota-

  tion in which the trigger lever also participates

  2 a When stopping against the user, the lever

  trigger 2 a only has to carry out the maneuvering path,

  conditioned on the construction plan by the dimension-

  positioning spring 7, until the

brake is activated.

  When the rotation of the drilling tool is stopped and the drill turns empty the user must return the trigger lever 2a to its initial position in order to

stop the brake action.

  This can be done by the fact that the user pulls the trigger lever towards himself so as to make him

  carry out the maneuvering path so that the lever

  trigger returns to its starting position, namely the posi-

  However, the user can also restore this starting position by returning the release lever 2, fitted with a handle, to its position.

  since the trigger levers 2 and 2 a are re-

rigidly linked together.

  The embodiment of Figure 3 can be such that the trigger lever 2, which does not have

  additional inert movable mass, can nevertheless

  apply the brake by its moment of inertia, in which case an additional triggering effect can be obtained from

  causes the trigger lever 2 a, provided additionally

nel, abuts the operator.

  In the third embodiment, represented

  felt in FIG. 4, the trigger lever 2 a, as it has been described in connection with FIG. 3, is formed exclusively by a bar 2 ′ forming a lever of comparatively low mass which, also in the manner described, triggers braking by abutting against the operator's body The trigger lever 2 'a therefore also exceeds the drilling tool so that, in the event of an inadvertent rotation of the drilling tool, it can abut against the user and

  activate the braking mechanism 3.

  Advantageously, the trigger levers 2 a and

  2 'a may, in accordance with the embodiments of the

  gures 3 and 4, present a joint 2 c, for example a

  helical spring or the like, so that the

  outer tie 2 b of the trigger lever 2 a can, when the latter abuts against the user, deflect flexibly Injury caused by the trigger lever 2 a; 2 'a, produced in the form of a bar, are thus excluded At the same time the latter is protected against damage during use since it can, for example in the case of transport, be folded and brought into a position rest

protected.

  Furthermore, the articulation 2 c is obviously

  due rigid enough for the trigger lever 2a;

  2 'a can as a whole, that is to say including its part

  outer tie 2 b, when abutting against the user, transmits

  be the displacement force necessary to trigger the

braking mechanism 3.

  The three examples of realization all have in com-

  fitted with the structure of the safety braking mechanism 3,

  it being produced in the form of an intermediate piece of the flange type which has a carrier body 5 in which are housed all the constituent elements necessary for the braking function so as to form a compact and independent assembly which, due to its small footprint does

  changes the drilling tool not significantly, as far as

  its construction and weight, and can easily be in-

  incorporated in both new and already existing drilling tools For this, the safety braking mechanism 3,

  i.e. the intermediate piece, is simply fixed in-

  be the motor 4 and the gearbox 14, holes for

  in this respect be provided, for example, as elements

  for fixing and screws or studs for example as a

fixing hoses 13.

  1 1 In all the exemplary embodiments the trigger lever 2; 2 a; 2 'a is mounted, by means of the axis 20 guided in the hole 19, so as to be able to tilt so

  limited on one maneuvering path The position spring-

  nement 7 engages in a recess 2 'forming notch (see Figure 5) of the trigger lever 2; 2 a; 2 'a and maintains it in the position where the brake is released In this regard the retaining force of the spring 7 is such that it is overcome by the critical acceleration force in the embodiment of Figure 1 or by the operating path of the trigger levers 2 a; 2 'a In all

  exemplary embodiments the carrying body 5 encloses the tam-

  bour 10 of the centrifugal clutch 1, the clutch drum being provided with a driving pinion which establishes the form connection with the gearbox 14 The arrangement is further such that the clutch drum 10 is located surrounded by the brake tape 6 at least almost completely and, preferably, several times The brake tape 6 is fixed by one of its ends at 15 in the carrier body 5, while the other free end of the tape brake 6 is located, via the toggle joint 9, in

  working relationship with trigger lever 2 and the

  tensioning spell 8 As already indicated, the safety braking mechanism 3 owes its compact construction mode to the fact that it comprises a carrier body 5 adapted to the crankcase and to the gearbox and in which all the essential constituent elements are housed. , namely the brake band 6, the positioning spring 7, the tension spring 8 and the toggle joint 9 In this regard, as shown

  the drawing, the arrangement may be such that, excessively

  relative to an at least approximately circular recess 21, disposed in the carrying body 5, there is provided a recess 22 contiguous to this circular recess 21 and in which are housed the additional spring 8, the toggle joint 9, the spring of positioning 7 and a terminal part 2 ", preferably angled, of the trigger lever 2 with its articulation axis 20 The knee joint

  9 can be carried out in an appropriate manner; in the example

  full of realization the toggle joint 9 is reali-

  Seed in the form of a lever with two arms which can rotate about the axis 23, the lever receiving the end of the tension spring 8 being articulated in connection with the articulation axis 20 by means of a fastener 24 and an intermediate lever 25 At the other end of the lever with two arms 9 ′ is fixed, in an appropriate recess, the free end of the

brake tape 6.

  The safety brake of Figures 1 to 3 can be triggered, either because the trigger lever 2 bears against the user as a result of relative rotation

  of the drilling tool relative to the latter, ie

  When suddenly there is an angular acceleration, exceeding a limit value, of the drilling tool, for which the trigger lever 2 triggers the braking process by virtue of its inert mass The sensitivity of the trigger can be adjusted by moving the inert mass 16 on the trigger lever 2 If the braking process is triggered, the toggle joint 9 passes

  beyond neutral so that the spring tends to

  Deur 8 stiffens the brake tape 6 and that the latter surrounds

  the drum 10 of the centrifugal clutch 1 in dynamic connection

  that the direction of rotation, designated in the figures by N, of the clutch drum 10 and of the driving pinion it connected to this

  last is such that self-strengthening occurs, that is

  i.e. assisted braking, between the brake band 6 and the

clutch drum 10.

  If it occurs, during operation of

  the drilling tool according to the embodiment of the figure

  re 1 and / or the exemplary embodiments of FIGS. 3 and 4, at the level of the drill a resistance which brakes or even stops the drill then, as already described briefly, the constituent elements of the drilling tool, including the handles of guide 17, are caused to rotate about the axis of the drill, namely in the direction opposite to the direction of rotation N of the drill, in which case there is an angular acceleration In the embodiment of Figure 1 the movable trigger lever 2 will keep at this instant, because of its inert mass, first of all its adjusted position and will eventually follow, with delay, the angular acceleration The relative movement thus occurring between the carrier body 5 and the trigger lever 2 is set to profit, in the case of the embodiment of the drilling tool provided with an inert mass

  (see figure 1), to trigger the braking process

  ge In the two example embodiments of Figures 3 and 4

  the braking process is triggered by the levers

  trip devices 2 a; 2 ′ projecting laterally beyond the drilling tool, when the latter, once reached a determined angular tilting of the assembly of the drilling tool

  drilling, come up against the user.

  The knee joint 9 provided in the

  carrier body 5, pass, during the triggering process

  beyond its neutral position so that the spring

  deur 8, which is produced as a tension spring, places the brake band 6 against the clutch drum 10 and, therefore, the components of the carrier body

  set in motion are supported, via the ru-

  brake ban 6, in contact with the more or less blocked drill bit 18,

  so the user no longer needs to exercise

  full of restraint and does not run any danger, while the motor 4 can itself continue to run idle The advantage of the invention lies in that, during the braking process of the drill 18 due to resistances opposing drilling , the relative movement between the control motor 4 provided with the

  gearbox 14 and drill 18 is prevented automatic-

  ment, that is to say without operator intervention, to exit

  te that the latter is protected against reaction forces occurring suddenly at the level of the drilling tool, without the drive motor of the drilling tool itself having

need to be arrested.

  All the examples shown show an embodiment in which the intermediate part 3 is, from the construction point of view, integrated into the casing of the

  gearbox 14 so that the intermediate piece

  area and the gearbox housing form one

  seems in this respect the arrangement is advantageously such that the construction height, hitherto provided for the gearbox, does not need to be increased so that a simple replacement of the integrated gearbox housing, including the intermediate piece and the safety braking mechanism located therein, is also

  possible To avoid an increase in height

  construction of the gearbox casing 14 the brake band 6 is placed, in the embodiment of FIG. 2, only around the brake drum 10 mounted in the gearbox casing and the latter is made in such a way way that the other building blocks of the

  braking, namely the positioning spring 7, the spring

  tensioning spell 8, the toggle joint 9 and the mass

  inert 2, are housed in an annex part, laterally offset

  in relation to the casing proper of the gearbox 14 and having a recess 22 Thus the casing

  gearbox and the intermediate piece of the kind bri-

  can be produced in a simple and inexpensive manner,

  as a single unit without needing to

  both increase the axial height of the gearbox housing

speeds.

Claims (24)

Claims   1 Drilling tool to be guided manually and provided with a guide handle, a control motor, a gearbox as well as a centrifugal clutch placed between the engine and the gearbox, characterized in that a drilling lever is provided in the drilling tool (2; 2 a, 2 ′ a) as well as a braking mechanism (3) which is in working relationship with the latter and in that, in addition, the lever trigger (2; 2 a, 2 'a) is in working relationship with the braking mechanism (3) in such a way that, for a predefined limit value, an untimely rotational movement of the drilling tool, due to the causes the drill (18) to strike a resistance to drilling, the trigger lever (2;  2 a, 2 'a) triggers the braking mechanism (3). 2 drilling tool according to claim 1, characterized in that the trigger lever (2; 2a, 2 'a) is mounted on a carrier body (5) so as to be movable against   the retaining force of a positioning spring (7).   3 drilling tool according to claim 2, characterized in that the carrier body (5) comprises at least one of the following constituent elements brake tape (6); positioning spring (7); tension spring (8); toggle joint (9); trigger lever (2) with inert mass (16) and / or trigger lever (2 a, 2 'a) in the form of a bar,   these elements together forming the braking mechanism (3).   4 drilling tool according to claim 3, characterized in that the trigger lever (2) has an inert mass (2 ') whose importance is dimensioned so that, in the case of exceeding the limit value d '' an angular acceleration, due to a rotation of the drilling tool at the moment when the drill (18) encounters resistance to drilling, the retaining force of the trigger lever (2) in the released position of the braking mechanism (3) is exceeded and braking is triggered.   5 drilling tool according to claim 3, characterized in that the limit value is the angular interval that the trigger lever (2 a, 2 'a) traverses, in case of rotation of the drilling tool due to the fact that the drill (18) collides with resistance to drilling, until the lever   trigger (2 a) abuts against the user.   6 drilling tool according to any one of claims   3 and 4, characterized in that an inert mass (16) is   mounted, so that it can be moved in the longitudinal direction   dinal, on the trigger lever (2).   7 drilling tool according to any one of claims   3 to 6, characterized in that the trigger lever (2) is provided, via its hinge pin (20) in the carrier body (5), with an additional trigger lever (2 a) presented under the form of a bar projecting laterally beyond the drilling tool, so that, in the event of inadvertent rotation of the drilling tool with the trigger lever (2), the operator serves the bar forming limit stop lever for triggering the braking mechanism (3).   8 drilling tool according to any one of claims   3 and 5, characterized in that a trigger lever (2 'a) consists exclusively of a bar forming a lever of comparatively low mass so that the braking mechanism is triggered when this bar forming a lever   (2 'a) abuts against the body of the user.   9 drilling tool according to any one of claims   , 7 and 8, characterized in that the trigger lever (2 a,   2 'a) produced in the form of a bar has a joint   tion (2 c), for example in the form of a helical spring, so that its outer part (2 b) can deviate flexibly from the inner part (2 d) at moment to strike a stop.   Drilling tool according to any one of the claims   3 to 9, characterized in that the braking mechanism (3) is   made as an independent building element   dant, preferably in the form of an independent intermediate piece, in which are provided fixing elements (12) intended to fix it to the engine (4) and to the gearbox (14) by clamping, the fixing elements preferably being holes (12) in the carrier body (5)   intended to receive fixing screws (13).   11 drilling tool according to any one of claims   3 to 10, characterized in that the carrier body (5) comprises a drum (10) of the centrifugal clutch (1) and the clutch drum (10) has a driving pinion (11) intended to connect it in connection shaped to the gearbox (14), the clutch drum (10) being further surrounded by the brake band (6) and the brake band (6) being fixed by one of   its ends in the carrier body (5).   12 Drilling tool according to claim 11, characterized in that the other free end of the brake band (6) is, by means of the toggle joint (9), in working relationship with the trigger lever (2; 2 a) and the tensioning spring (8).   13 drilling tool according to any one of claims   3 to 12, characterized in that the positioning spring (7) is produced in the form of a leaf spring which bears with one of its ends against the trigger lever (2), while it is supported with its other end in contact with the carrier body (5) and in that the tension spring (8) is produced in the form of a tension spring between   the carrier body (5) and the toggle joint (9).   14 drilling tool according to any one of claims   3 to 13, characterized in that, eccentrically with respect to an at least approximately circular recess (21), located in the carrier body (5), are arranged, in at least one neighboring recess (22), the tensioning spring (8),   the toggle joint (9), the positioning spring   ment (7) and an end part (2 a), preferably bent,   trigger lever (2) with its hinge pin (20).   Drilling tool according to any one of the claims   3 to 14, characterized in that the braking mechanism (3) and the gearbox housing (14) are joined together to form a single whole.   16 Drilling tool according to claim 15, characterized in that, the intermediate part (3) and the gearbox (14) being produced in the form of a single assembly, the brake band is placed around the drum. clutch (10) arranged in the gearbox housing, and the other components of the safety braking mechanism (3), namely the positioning spring (7), the tensioning spring (8), the articulation to toggle (9) and inert mass (2) are housed in the recess (22) at least partially projecting laterally outside the casing of the gearbox (14).